Introduction to R for Data Science (Part Two)
This is the second introduction to R. This will cover matrix, matrix operations, factor matrices, and more.
*Originally published on my Substack. This is just a part of the article.
PS: Please read ‘Introduction to R for Data Science (Part One)’ before reading this one. This is a continued version of part one.
Vector Indexing and Slicing
We can use bracket notation to index and access individual elements from a vector
In the figure above, I use v1[2] to select the second number from v1. This would give me 200. I’ve also done it with v2[3] which gave me a “c”. Just remember that if you want to access individual elements, you would use a bracket.
In order to get multiple vectors, we would add a c after the bracket.
This would allow us to get multiple values as you can see above.
Slicing is where you can grab a continuous slice of vector.
Here I have assigned a new value. The colon(:) is where you would stop. So I would start at 2 and end at 4, which then it gave me 2, 3, and 4. Same thing as v[7:10], it would give me 7, 8, 9, 10.
We can also assign characters with numeric as we mentioned before. The difference is that instead of saying v[2], we can also say v[‘b’], which would give us the same result. To get multiple vectors, we can do the same before by using v[c(‘c’,’d’,a’)].
Read the full article here: https://ivanh.substack.com/p/introduction-to-r-for-machine-learning-604
